In recent years, more and more fluorescent lamps in lighting industry have been replaced by LED lamps using light-emitting diodes (LED) as light sources. The LED lamps are more efficient, energy-saving, and environmental-friendly. And the LED lamps have longer service life.
Linear LED lamps are also known as LED tubes. Currently, LED tubes in the market usually use tubular plastic light covers, for example, the plastic light covers may be made from polycarbonate (PC) material. The tubular light cover has two ends fixedly connected to two end-caps, and an LED light source board and a driving unit are installed inside the tubular light cover. As the LED tubes are used in different occasions and regions, even in the same area, the temperature changes will happen at different times, the tubular plastic light cover may have length variation due to thermal expansion and contraction in the case of temperature changes. For an LED tube, which has not been installed, if the LED tube becomes longer or shorter, it cannot be installed. For an LED tube, which has been installed in a lamp holder, if the LED tube becomes longer or shorter, the tubular plastic light cover will be bent and deformed in appearance, even the tubular plastic light cover will be disconnected with the end-cap, so that the LED tube will be damaged and there will be a danger of electric leakage.